State variations in the newborn and mother-infant interaction during breast feeding: Some sex differences

30 male and 33 female newborns were observed being breast-fed in the maternity ward. The conditional probabilities of various maternal and infant behaviors were studied when the infant was in 1 of 4 states: asleep, drowsy, fussy, and crying. Although male dyads showed more interactive activity on the asleep end of the scale, female dyads showed more interactive activity on the awake end of the scale. These interaction episodes were characterized by greater physical proximity in male dyads and more social interaction in female dyads. Although male neonates spent less time than females in the fussy state, when they were in this state, they seemed to be more agitated than the females. A relatively high proportion of simultaneous vocalization was observed in dyads of both sexes during the fussy state. Results are qualified by the great individual differences observed among the neonates in the amount of time spent in each of the states. (15 ref) (PsycINFO Database Record (c) 2006 APA, all rights reserved).